This invention relates to siloxane and siloxane copolymer masonry water repellent compositions, and more particularly is directed to a water repellent composition for treating porous substrates which is an emulsion including a copolymer such as a linear methylhydrogen-methylalkyl siloxane or a methylhydrogen-methylalkyl cyclosiloxane.
Water resistance is an important factor in concrete and masonry construction. This is for the reason that moisture movement in concrete causes or contributes to problems such as expansion, shrinkage, cracking, staining, mildew, lowered resistance to freezing and thawing, chemical attack, corrosion of reinforcing steel, and damage to structures from settling. Because of these problems, various techniques have been used to render concrete water resistant. Some of these methods include the surface treatment of concrete structures with water repellents. Water repellents that have been used in the past are oils, waxes, soaps, resins and organosilicon compounds, and they have been applied to the masonry surfaces by brush, roller, air spray, or airless spray techniques. One of the most prevalent category of repellent that has been used is organosilicon compounds, and such compounds in organic solvents have been found to be useful for brick, concrete, stucco, or terrazo surfaces.
It is not new in the art to employ organosilicon compounds for the treatment of masonry surfaces in order to render such surfaces water repellent. For example, in U.S. Pat. No. 3,772,065, issued Nov. 13, 1973, there is disclosed an impregnant which is an alcohol or hydrocarbon solution of alkyltrialkoxysilanes or oligomers thereof. In U.S. Pat. No. 3,849,357, issued Nov. 19, 1974, a composition is described which is a mixture of a water base paint, and the reaction product of an alkyltrialkoxysilane, an alkyl orthosilicate, and water. U.S. Pat. Nos. 3,389,206, issued Apr. 22, 1975, and 4,002,800, issued Jan. 11, 1977, there is disclosed a solution containing an alcohol or hydrocarbon solvent, an alkyltrialkoxysilane, and an additive. The additive is either an organofunctional silane such as aminopropyltriethoxysilane or an alcoholate such as butyl titanate. U.S. Pat. No. 3,914,476, issued Oct. 21, 1975, refers to an aqueous solution containing an alkali metal organosiliconate, and an aqueous soluble carbonate or bicarbonate. In U.S. Pat. No. 3,955,985, issued May 11, 1976, an aqueous solution is described containing an alkali metal organosiliconate, a miscible alcohol or ketone, and an organic complexing or chelating agent such as nitrilotriacetic acid.
U.S. Pat. No. 3,956,570, issued May 11, 1976, applies an aqueous solution of an alkali metal propylsiliconate. Surfaces are contacted with water followed by treatment with a mixture of calcium hydroxide and butyltrimethoxysilane in ethyl alcohol in U.S. Pat. No. 4,073,972, issued Feb. 14, 1978. In U.S. Pat. No. 4,076,868, issued Feb. 28, 1978, there is applied a solvent solution thickened with a filler, and containing either (i) a polysiloxane having a viscosity less than 1000 cs, (ii) an alkyltrialkoxysilane, or (iii) an alkali metal hydrocarbon siliconate. U.S. Pat. No. 4,102,703, issued July 25, 1978, forms a stable suspension of hydrophobed metal oxides in ethylene glycol, and applies the suspension to masonry. Hydrophobing is accomplished with either (i) organohalosilanes, (ii) organosilylamines, (iii) cyclic organosilazanes, (iv) organocyclosiloxanes, (v) polyorganosiloxanes, (vi) alkylhydrogen silicone oils, or (vii) hydroxy endblocked polyorganosiloxanes.
In U.S. Pat. No. 4,209,432, issued June 24, 1980, the patentee applies a solvent solution containing a filler such as fume silica, and containing either (i) an organosiloxane having more than ten silicon atoms per molecule, (ii) an alkyltrialkoxysilane, (iii) the reaction product of a silane and ethylene glycol, or (iv) an alkali metal hydrocarbon siliconate. U.S. Pat. No. 4,273,813, issued June 16, 1981, employs a coating of an emulsion of an anionically stabilized hydroxy endblocked polydiorganosiloxane, amorphous silica, and an organic tin salt. In U.S. Pat. No. 4,342,796, issued Aug. 3, 1982, the patentee dries the surface to be treated, applies an alkyltrialkoxysilane to the dried surface, allows the silane to migrate into the surface, and applies water to the treated surface. U.S. Pat. No. 4,352,894, issued Oct. 5, 1982, applies an aqueous solution of an alkylsilanol prepared from propyltrimethoxysilane. A coating of a moisture curable urethane resin and an alkylpolysiloxane or hydroxyalkyl polysiloxane such as 2-ethyl-hexyl polysiloxane, stearyl polysiloxane, or hydroxyethyl polysiloxane, is disclosed in U.S. Pat. No. 4,413,102, issued Nov. 1, 1982. In U.S. Pat. No. 4,433,013, issued Feb. 21, 1984, there is applied an emulsion of an akyltrialkoxysilane including a deactivatable surfactant such as a fatty acid ester or silica ester. After the emulsion is applied, the surfactant is deactivated with water containing an alkaline or acid substance. U.S. Pat. No. 4,478,911, issued Oct. 23, 1984, relates to a coating which includes an alkyltrialkoxysilane, water, an organic solvent, and a catalyst such as an organic amine. In U.S. Pat. No. 4,486,476, issued Dec. 4, 1984, the patentee impregnates with a water immiscible solvent such as naphtha containing a mixture of a methyl-ethoxysiloxane having an ethoxy content of 12 percent and a methyl-ethoxysiloxane having an ethoxy content of 43 percent.
U.S. Pat. No. 4,631,207, issued Dec. 23, 1986, employs a solvent such as a glycol ether containing the reaction product of octamethylcyclotetrasiloxane and N-(2-aminoethyl)-3-aminopropyl dimethoxy-methylsilane. Reexamined U.S. Pat. No. Bl 4,648,904, issued Mar. 10, 1987, is directed to an emulsion of an alkyltrialkoxysilane, an emulsifier having an HLB value of 2-20, and water. A solution containing an alkylalkoxy polysiloxane resin is applied to masonry in U.S. Pat. No. 4,717,599, issued Jan. 5, 1988. An oily composition or emulsion is disclosed in U.S. Pat. No. 4,741,773, issued May 3, 1988, containing a mixture of a silicone oil with either a nonvolatile paraffinic oil such as turbine oil or a nonvolatile low molecular weight hydrocarbon resin such as polybutene. In U.S. Pat. No. 4,753,977, issued June 28, 1988, the treating composition includes an organopolysiloxane resin, an alkylalkoxy polysiloxane resin, and a condensation catalyst. A sealer including a hydroxy-substituted polyorganosiloxane and a mixture containing (i) an aromatic solvent such as toluene, (ii) a chlorinated solvent such as trichloroethane, and (iii) an aliphatic solvent such as heptane, is taught in U.S. Pat. No. 4,786,531, issued Nov. 22, 1981.
In U.S. Pat. No. 4,846,886, issued July 11, 1989, and in U.S. Pat. No. 4,874,431, issued Oct. 17, 1989, the patentees apply a combination of (i) a carrier such as an alcohol, glycol ether, or mineral spirits, (ii) a metal salt catalyst, (iii) an alkylalkoxysilane, and (iv) a beading agent such as a fluorosilicone fluid, a polydimethylsiloxane fluid, a room temperature curable silicone rubber, an amine salt functional siloxane copolymer, or trimethylsilyl endcapped polysilicate. A buffered aqueous silane emulsion is disclosed in U.S. Pat. No. 4,877,654, issued Oct. 31, 1989, and U.S. Pat. No. 4,889,747, issued Dec. 26, 1989, containing a hydrolyzable silane, an emulsifier with an HLB value of 1.5-20, water, and a buffering agent.
As noted, it is not new to treat masonry surfaces with organosilicon compounds for the purpose of rendering the masonry water repellent. One category of organosilicon compound which has been used extensively is the alkoxysilane, and representative of such masonry treatments with alkoxysilanes can be found in U.S. Pat. No. 3,772,065, issued Nov. 13, 1973; U.S. Pat. No. 3,879,206, issued Apr. 22, 1975; U.S. Pat. No. 4,478,911, issued Oct. 23, 1984; U.S. Pat. No. 4,648,904, issued Mar. 10, 1987; U.S. Pat. No. 4,846,886, issued July 11, 1989; and U.S. Pat. No. 4,874,431, issued Oct. 17, 1989. Another category of organosilicon compound frequently used in masonry treatment is the siloxane. Representative of such masonry treatments with siloxanes can be found in U.S. Pat. No. 4,209,432, issued June 24, 1980; U.S. Pat. No. 4,342,796, issued Aug. 3, 1982; and U.S. Pat. No. 4,753,977, issued June 28, 1988. The present invention includes siloxanes in one embodiment and the siloxanes of that embodiment differ from the siloxane compositions of the prior art in the presence in the siloxane molecule of the silylidyne radical ##STR1## This difference is significant as will be pointed out hereinafter.